Process for the vulcanization of rubber



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@atentecl Oct. 22, 192.

UNITED STATES PATENT OFFICE WJLNFIELD SCOTT, OF NITRO, WEST VIRGINIA, ASSIGNOR TO THE RUBBER SERVICE LABORATORIES 00., OF AKRON OHIO, A CORPORATION OF OHIO PROCESS FOR THE VULCANIZATION 0F RUBBER lto Drawing. I

The present invention relates to the vulcanization of rubber by an improved process wherein the products obtained by reacting mercapto-aryl-thiazoles, their alkaline salts and the like, with 2,4 dinitrochlorbenzene are employed as vulcanization accelerators. It is Well known among rubber chemists that the mercapto-aryl-thiazoles constitute a valuable group of vulcanization accelerators. It has now been found that on reacting mercapto-aryl-thiazoles, such for example as the potassium salt of mercapto-benzothiazole and the like, with dinitrochlorbenzol there is formed an important class of compounds which may be used alone as a vulcani- .zation accelerator or preferably in conjunction with air organic amine accelerating compound to form a mixed accelerator. it has furthermore been found that when used either alone or as part of a mixed accelerator, of which thp other component is an organic amine accelerating compound, very little vulcanization takes place at the lower temperatures. Such delayed action on the part of vulcanization accelerators is of particular importance, as it prevents partial curing of the rubber taking place during the milling op erations or at other times prior to the actual vulcanization process.

The invention will be fully understood from the following description and examples.

Rubber stoclrs were compounded in the usual manner comprising 100 parts of pale crepe rubber, 5 parts of zinc oxide, 6 parts of sulfur and 0.5 parts and also 1.0 part respectively of the reaction product of 2,41.- dinitrochlorbenzene and the potassium salt of mercapto-benzo-thiazole. Un testing strips of the above described stock vulcanized by heating in a press for difierent periods of time under temperatures given by diflerent steam pressures, the following tensile data were obtained.

Application filed August 6, 1928.

Serial No. 297,919.

Modulus of elasticity in Preslbs. in. t 1 Elonga- Cure sure 2253 On/S f a e onga Tensile tion at min. lbs. at ak break steam 30017 500 e 3U 40 O. 5 112 262 768 1715 850 1. 0 140 365 1200 2715 850 40 0. 5 162 369 1101] 2310 830 45 40 1. 0 215 505 1585 2940 810 60 40 O. 5 182 413 1335 2330 808 00 40 1. O 253 592 1795 2955 785 90 40 0. 5 219 453 1275 2590 820 90 40 1. O 271 649 1820 3100 795 120 10 0. 5 216 488 1375 2385 795 120 40 1 0 273 648 1865 2470 735 From the above results it is evident that the reaction product set forth possesses desirable vulcanization accelerating properties. These properties are increased by operating in the-manner as hereinafter set forth.

In all tests hereinafter described, the reaction product of 2,4. dinitrochlorbenzene and the potassium salt of mercapto-benzothiazole is designated as accelerator A.

To show the action of this preferred class of accelerator in conjunction with an organic amine accelerating compound, a rubber stock was compounded in the usual manner comprising 100 parts of pale crepe rubber, 5 parts of zinc oxide, 3.5 parts of sulfur, 0.3 parts of accelerator A, 0.4 parts of an organic amine accelerating compound as shown in the table below.

On testing strips of the above stock, vulcanized by eating in a press for did'erent periods of time at difierent temperatures, the following tensile data were obtained.

a Modulus of *3 g elasticltyin 3 w lbsJin. at is n elongations 2 5 Accelerating mlxture.-O0ntd. g 5 f g E E w a a s t 1.. .2 o m w 6 1 "A"diphenet1dylguan1dine 30 10 125 247 6381660 900 A 4, 4 tetra-methyl diammo methylene dianillde 30 10 111 201 5351825 940 "A" phenyl-penta-methylene thiourea 30 10 55 92 137 4581010 A hem-methylene tetramine 30 10 No cure. A"g;phenylene di amine. 30 10 82 137 2 601 840 "A 1pheny1-guan1dine-. 60 10 151 36213902735 840 "A" mono-o-tolyl biguanlde- 60 10 69 147 39111300 950 Apiperazine 60 10 111 219 5561635 930 "A" diphenetidyl guanidin 60 10 225 491 1820 3350 830 A 4, 4 tetra-methyl d1 methylene dlamllde- 60 10 231 49016703095 820 oiir d Dents-me 60 10 127 247 7261735 870 A"hexa-methylene tetr 60 10 62 123 243 651 910 A phenylene diamine- 60 10, 193 41013852640 840 A diphenyl-guanidme 30 20% 177 35611952610 840 Amono-o;toly1biguamde 30 20 77 173 3831025 920 A"pi perazm e 30 20 112 208 5161790 960 A diphenetidylguan1dine 30 20 219 48017903295 820 A" 4, 4 tetra methyl diamm methylene dianilide 30 20 181 45519803450 830 A" phenyl petite-methylene thio- 20 urea 30 130 260 778 2150 903 A"hexa-methylene tetramine- 30 20 84 164 3841155 950 A p-phenylene di amine- 30 20 186 400 1380 2745 853 A"diphenyl g'uamdine 60 20 275 7162640 3370 750 mono-o-tolyl biguanide. 228 174 371 1225 2555 850 piperazine 208 42214102625 830 Adiphenetldyl g'uanidin e 60 20 317 776 31654000 750 A 4, 4' tetra-methyl diammo methylene dianilide 60 20 315 810 33% 4010 750 Aphenylpenta-methylenethw- 60 20 21 20 urea 2 506200116200 8 11" hem-methylene tetramine. 60 20 199 44416002820 830 Ap-phenylene diamme. 60 20 308 715 2500 3480 768 14" diphenyl guan dmem 15 40 255 597 21503355 790 mono-o tolyl b1guanide. 44g 130 242 755i1860 870 piperazine 167 302 911 2020 870 A diphenetidyl guenidine 15 40 292 694 27103580 770 "A" 4, 4' tetra-methyl diamlno i methylene dianillde 15 40 260 666 26753555 750 "A" phenyl penta-methylene thi- 40 oul'ea 15 181 369126512680 830 "A"hexa-methylene-tetramine 15 40 142 290 9342195 870 "A p phenylene d amme 15 40 206 460 1670,3210 820 Ad1pheny1-guamdine 30 40 296 809296513730 760 A" mono-o tolyl biguan 30 40 185 36812502485 840 A piperazine 30 40 180 396 13152680 850 A diphenetidyl guanid 30 40 362 935 36804040 730 Atg, 14 tgtra-iirligthyl diamino 30 4 29 i 60 me yene iani e 0 5 76129903920 7 A phenyl-penta-methylene thiourea 30 40 278 585 %10 3155 793 Ahexa-methylene tetramine.. 30 40 213 545 mm 2105 800 A p-phenylene diarnine 30 40 271 645 mm 4250 770 A dipheny1guanidine 45 40 342 808 3195 3525 720 mono-o-tolyl biguanidm 45 i3 139 436 1465 2430 8% piperazine 45 1 1 38713252705 8 "A"diphenetidyl guanidine 45 40 366 995 3770 4080 730 A 4, 4 tetra-methyl diammo methylene dianilide 45 40 349 845 3255 3900 760 14"phenylpenta-methylenethio- 45 40 27 n 770 urea 6 6 5 +05 Ahexa-methy1ene tetramine 45 40 68 668 2305 3010 770 A p-phenylene djamine v45 40 269 6522280 3475 7 A" diphenyl guanidine 60 40 354 870 39102600 750 A mono-o-tolyl biguanide 60 40 244 4901625 2635 800 "A" iperezine 60 40 197 3961315 2740 840 "A" diphenetidyl guanidine" 60 40 406 1025 4010 4090 720 "19. 4, 4 tetra methyl diammo methylene dianilide 60 40 309 790 3040 3740 760 ill phenyl penta methylene 0 40 37 554 2120 3325 793 iourea 6 2 r A here-methylene tetra 60 40 266 667 248513395 780 A"p-pheny1ene diamine 60 40 270 636 228513350 790 The above results very clearly show the desirable accelerating properties of the class of compounds and mixtures thereof as herein disclosed. Thus, when the mixtures of accelerators set forth are employed in a rubber stock cured at lower temperatures, but slight, if any curing action is produced. This fact enables such accelerating mixtures to be employed without producing a set cure, scorching or other undesired results produced by pre-vulcanization of the stock during the milling or calendering of the stock or at any other stage or step carried out in the manufacture of a rubber product prior to the actual vulcanization thereof. On the .other hand, the results obtained at full cure show that a vulcanizate is produced which possesses particularly characteristic and desirable properties.

The foregoing examples are to be understood as illustrative only and not at all limitative of the invention. Other vulcanized products may be obtained by employing other compounding ingredients and other proportions of ingredients than those particularly set forth in the examples.

hat is claimed is:

1. The process of producing vulcanized rubber which comprises heating rubber and sulfur in the presence of a mixture of accelerators, said accelerators comprising the reaction product of dintrochlorbenzene and an alkaline salt of mercapto-benzo-thiazole, and a basic organic nitrogen-containing vulcanization accelerator.

2. The process of producing vulcanized rubber which comprises heating rubber and sulfur in the presence of a mixture of accelerators, said accelerators comprising the reaction product of dinitrochlorbenzene and the potassium salt of mercapto-benzo-thiazole, and a basic organic nitrogen, containing vulcanization accelerator.

3. The process of producing vulcanized rubber which comprises heating rubber and sulfur in the presence of a mixture of accelerators, said accelerators comprising the reaction product of dinitrochlorbenzeue and the potassium salt of mercapto-benzo-thiazole, and a secondary amine accelerating compound.

4. The process of producing vulcanized rubber which comprises heating rubber and sulfur in the presence of a mixture of accelerators, said accelerators comprising the reaction product of dinit-rochlorbenzene and thepotassiumsaltof mercapto-benzo-thiazolc, and an aryl substituted secondary amine accelerating compound.

5. The process of producing vulcanized rubber which comprises heating rubber and sulfur in the presence of a mixture of accelerators, said accelerators comprising the reaction product of dinitrochlorbenzene and thepotassiumsaltof mercapto-benzothiazole, zole, and diphenyl-guanidine.

6. The process of producing vulcanized rubber which comprises heating rubber and sulfur in the presence of a vulcanization accelerating product containing the reaction product of dinitrochlorbenzene and an alkaline salt of mercapto-benzo-thiazole as a constituent thereof.

7. The process of producing vulcanized tion product of dinitrochlorbenzene and the rubber which comprises heating rubber and potassium salt of mercapto-benzo-thiazole. sulfur in the presence of a vulcanization ac- In testimony whereof I hereunto aflix my celerating product containing the reaction i t e, 5 product of dinitrochlorbenzene and the potas- WINFIELD SCOTT.

sium salt of mercapto-benzo-thiazole as a constituent thereof.

8. The vulcanized rubber product prepared by heating rubber and sulfur in the presence w of a mixture of accelerators, said accelerators comprising a reaction product of dinitrochlorbenzene and an alkaline salt of Inercapto-benzo-thiazole, and a basic organic nitrogen-containing vulcanization accelerator. w 9. The vulcanized rubber product prepared by heating rubber andsulfur in the presence of a mixture of accelerators, said accelerators comprising the. reaction product of dinitrochlorbenzene and the potassium salt of merm capto-benzo-thiazole, and a basic organic nitrogen-containing vulcanization accelerator.

10. The vulcanized rubber product prepared by heating rubber and sulfur in the presence of a mixture of accelerators, said accelerators comprising the reaction product of dinitrochlorbenzene and the potassium salt of mercapto-benzo-thiazole and a secondary amine acceleratin compound.

w ll. The vulcanized ru%ber product prepared by heating rubber and sulfur in the presence of a mixture of accelerators, said accelerators comprising the reaction product of dinitrochlorbenzene and the potassium M salt of mercapto-benzo-thiazole, and an aryl substituted secondary amine accelerating compound.

12. The vulcanized rubber product prepared by heating rubber and sulfur in the m presence of a mixture of accelerators, said accelerators comprising the reaction product of dinitrochlorbenzene and the potassium salt of mercapto-benzo-thiazole, and diphenyl-guanidine 45 13. The vulcanized rubber product prepared by heating rubber and sulfur in'the presence of a vulcanization accelerating product containing the reaction product of dinitrochlorbenzene and an alkaline salt of W mercapto-berizathiazole as a constituent thereof.

ill. The vulcanized rubber product prepared by heating rubber and sulfur in the presence of a vulcanization accelerating prod- 55 uct cotaining the reaction product of dinitrochlorbenzene and the potassium salt of mercapto-benzo-thiazole as a constituent thereof,

m 15.. A vulcanization accelerator mixture comprising an organic amine and the reaction product of dinitrochlorbenzene and the potas sium salt of mercaoto-benzo-thiazole.

16. A vulcanization accelerator mixture at omprising diphenyl-guani u d the ream DISCLAIMER 1,732,486.W'injield Scott, Nitro, W. Va. PRocEss FOR THE VULCANIZATION or RUB- BER. Patent dated October 22, 1929. Disclaimer filed January 14, 1932, by the assignee, The Rubber Service Laboratories Company.

Does hereby disclaim that part of the claim in said specification which appears therein as claims 2, 3 ,6, 7, 9, 10, 18, 14 and 15 thereof, and does hereby disclaim from claims 1, 4, 8 and 11 thereof, any process as to claims '1 and 4 and any product as to claims 8 and 11 excepting a process or a product, respectively, wherein the aryl substituted secondary amine accelerating compound as pointed out in each of said claims 4 and 11, or the basic organic nitrogen-containing vulcanization accelerator as pointed out in each of said claims 1 and 8, contains in its molecular structure a carbon atom of a benzene nucleus directly attached to a nitrogen atom of an amino group and another group of atoms attached to this notrogen atom.

Your petitioner further says that the subject matter not herein and hereby disclaimed is definitely distinguishable from the part or parts disclaimed herein and is truly and justly the invention of said Winfield Scott, and is a material and substantial part of the thing patented.

[Ofiicial Gazette February .9, 1932.] 

